Thermally Conductive Polymer Compositions Containing Carbon Black

ABSTRACT

A composite polymer composition comprising partially crystallized carbon black. The composition exhibits superior thermal transfer properties in plastic formulations. The polymer precursor exhibits excellent rheology when compared to similar compositions comprising traditional carbon blacks. The composite polymers provide for higher loading of more thermally conductive carbon blacks in a variety of composite polymer compositions.

FIELD OF THE DISCLOSURE

The present disclosure relates to polymer compositions and, inparticular, to plastics exhibiting improved thermal conductivity andmechanical properties.

BACKGROUND

Polymer systems that can benefit from improved heat transfer are used ina variety of fields including electronic, mechanical, automotive,aerospace and industrial applications. For example, conductive polymerscan be used in wire and cable jacketing to dissipate heat from the cablecore. Thermally conductive polymers can also replace materials such asmetals or less thermally conductive materials that are typically used inapplications that require efficient transfer of heat.

SUMMARY

In one aspect, a composite polymer composition is provided, thecomposite polymer composition comprising a polymer matrix and apartially crystallized carbon black dispersed in the polymer matrix at aconcentration of from 12 to 28 percent by weight, wherein the carbonblack has an OAN structure of greater than 120 cm³/100 g and less than200 cm³/100 g, a surface energy of less than 8 mJ/m², a percentcrystallinity of less than 65% and a Raman microcrystalline planar size(L_(a)) of greater than or equal to 28 Å. The partially crystallizedcarbon black can be formed by thermally treating a furnace black at atemperature greater than 700° C. and less than 1800° C. The compositioncan comprise a copolymer or terpolymer. The polymer composition can be apolyolefin, a polystyrene, a polycarbonate, a polyamide, and/or apolyamine. The carbon black can have a Raman microcrystalline planarsize (L_(a)) of greater than or equal to 35 Å and a surface energygreater than 1 mJ/m². The polymer can be selected from thermoplasticpolyolefins (TPO), polyethylene (PE), linear low density (LLDPE), lowdensity (LDPE), medium density (MDPE), high density (HDPE), ultra-highmolecular weight (UHMWPE), very low density polyethylene (VLDPE),metallocene medium density polyethylene (mLLDPE), polypropylene,copolymers of polypropylene, ethylene propylene rubber (EPR), ethylenepropylene diene terpolymers (EPDM), acrylonitrile butadiene styrene(ABS), acrylonitrile EPDM styrene (AES), styrene-butadiene-styrene(SBS), polyoxymethylene (POM), polyamides (PA) polyvinylchloride (PVC),tetraethylene hexapropylene vinylidenefluoride polymers (THV),perfluoroalkoxy polymers (PFA), polyhexafluoropropylene (HFP),polyketones (PK), ethylene vinyl alcohol (EVOH), copolyesters,polyurethanes (PU), thermoplastic polyurethanes, polystyrene (PS),polycarbonate (PC), polybutylene terephthalate (PBT), polyethyleneterephthalate (PET), polypheneylene oxide (PPO) and polyphenylene ether(PPE). The composition can be a masterbatch. The composition may furtherinclude a non-carbonaceous particle having a thermal conductivitygreater than 30 W/mK, for example, boron nitride, magnesium oxide, zincoxide, or alumina. The volume ratio of partially crystalized carbonblack to the non-carbonaceous particle, e.g., boron nitride, may be from1:1 to 1:10. The composite polymer composition may have a thermalconductivity at least 1.6× greater, at least 1.7× greater, or 2-4 timesgreater than the thermal conductivity of the polymer matrix. Thepartially crystallized carbon black may improve a thermal conductivityof the composite polymer composition at least 10% with respect to anuntreated carbon black.

In another aspect, a polymer precursor composition is provided, thecomposition comprising a polymer precursor comprising a polymerizablemonomer or oligomer and a partially crystallized carbon black dispersedin the monomer or oligomer at a concentration of from 12 to 28 percentby weight, wherein the carbon black has an OAN structure of greater than120 cm³/100 g and less than 200 cm³/100 g, a surface energy of less than8 mJ/m² and a Raman microcrystalline planar size (L_(a)) of greater thanor equal to 28 Å. The polymer precursor may be a precursor of a polymerselected from a polyolefin, a polystyrene, a polycarbonate, a polyamide,and/or a polyamine. The polymer precursor can be a precursor of apolymer selected from thermoplastic polyolefins (TPO), polyethylene(PE), linear low density (LLDPE), low density (LDPE), medium density(MDPE), high density (HDPE), ultra-high molecular weight (UHMWPE), verylow density polyethylene (VLDPE), metallocene medium densitypolyethylene (mLLDPE), polypropylene, copolymers of polypropylene,ethylene propylene rubber (EPR), ethylene propylene diene terpolymers(EPDM), acrylonitrile butadiene styrene (ABS), acrylonitrile EPDMstyrene (AES), styrene-butadiene-styrene (SBS), polyoxymethylene (POM),polyamides (PA) polyvinylchloride (PVC), tetraethylene hexapropylenevinylidenefluoride polymers (THV), perfluoroalkoxy polymers (PFA),polyhexafluoropropylene (HFP), polyketones (PK), ethylene vinyl alcohol(EVOH), copolyesters, polyurethanes (PU), thermoplastic polyurethanes,polystyrene (PS), polycarbonate (PC), polybutylene terephthalate (PBT),polyethylene terephthalate (PET), polypheneylene oxide (PPO) andpolyphenylene ether (PPE). The polymer precursor can be a precursor fora polymer selected from the group consisting of acrylics, epoxies,silicones, phenolics, polyimides, plastisols, and polyvinyl acetates.The polymer precursor can comprise a precursor of a polyolefin, apolystyrene, a polycarbonate, a polyamide, and/or a polyamine. Thecomposition may further include a non-carbonaceous particle having athermal conductivity greater than 30 W/mK, for example, boron nitride,magnesium oxide, zinc oxide, or alumina. The volume ratio of partiallycrystalized carbon black to the non-carbonaceous particle, e.g., boronnitride, may be from 1:1 to 1:10. The polymer precursor composition,following polymerization, may have a thermal conductivity at least 1.6×greater, at least 1.7× greater, or 2-4 times greater than the thermalconductivity of a polymerizate of the polymer precursor. The partiallycrystallized carbon black may improve a thermal conductivity of apolymerizate of the polymer precursor composition by at least 10% withrespect to an untreated carbon black.

In another aspect, the composite polymer composition or polymerprecursor composition includes a carbon black having a Ramanmicrocrystalline planar size (L_(a)) of greater than 29, 30, 31 or 35 Åand/or less than 65, 60, 55, 50 or 45 Å. The surface energy of thecarbon black can be less than 4, less than 3 or less than 2 mJ/m² and/orgreater than 0 mJ/m². The carbon black can have a percent crystallinityof greater than or equal to 35%, 40%, 45%, 50%, 55% or 60%. The BETsurface area of the carbon black can be less than 425 +/−25, less than300, less than 250, from 40 to 400 m²/g, from 46 to 400 m²/g, from 40 to300 m²/g, or from 40 to 200 m²/g. The composite polymer composition orpolymer precursor composition can be used to make products such as wireand cable jacketing, 3D printed products, automotive parts, and LEDcasings and fixtures. The carbon black can exhibit a substantiallypolyhedral primary particle shape and may have an iodine number of lessthan 425 m²/g, less than 350 mg/g, less than 300 mg/g, less than 250mg/g or less than 200 mg/g. The carbon black can be an unmodified carbonblack. The composite polymer composition or polymer precursorcomposition can include a second carbon black that may or may not bepartially crystallized. The partially crystallized carbon black can bemade by increasing the Raman microcrystalline planar size (L_(a)) of abase carbon black by greater than 5, greater than 10, greater than 15 orgreater than 20 Å.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a bar graph comparing the thermal conductivity of a basecarbon black with two embodiments of a partially crystallized carbonblack derivative;

FIG. 2 is a bar graph comparing the thermal conductivity of a secondbase carbon black with three embodiments of a partially crystallizedcarbon black derivative;

FIG. 3 is a bar graph comparing the thermal conductivity of a third basecarbon black with an embodiment of a partially crystallized carbon blackderivative;

FIG. 4 is a bar graph comparing the thermal conductivity of a fourthbase carbon black with an embodiment of a partially crystallized carbonblack derivative;

FIG. 5 is a bar graph comparing the thermal conductivity of a fifth basecarbon black with an embodiment of a partially crystallized carbon blackderivative;

FIG. 6 provides a graph illustrating the thermal conductivity of threepolymer composites, each including a different filler;

FIG. 7 provides a graph illustrating the thermal conductivity of thepolymer composites of FIG. 6 as well as two comparative examples thatinclude both boron nitride and carbon black particles;

FIG. 8 provides a graph illustrating the thermal conductivity of thepolymer composites of FIG. 7 as well as a third embodiment of a polymercomposite that includes a highly thermally conductive particle and apartially crystallized carbon black particle.

DETAILED DESCRIPTION

In one aspect a polymer system is provided that includes at least onepolymer and at least one partially crystallized carbon black. Partiallycrystallized (also referred to as partially graphitized) carbon blacksexhibit higher crystallinity and lower surface energy than theircorresponding base carbon blacks and, as described below, can provideimproved thermal transfer capabilities compared to less crystallineforms of carbon black. As illustrated herein, partially crystallizedcarbon blacks can also improve the rheology of the polymer precursorsthat they are dispersed in when compared to similar systems usingconventional carbon blacks. The polymer systems described herein may beany synthetic polymer in which a partially crystallized carbon black canbe dispersed to improve thermal transfer efficiency. In addition, wehave found that carbon blacks subjected to excess crystallization do notprovide the enhanced thermal conductivity properties exhibited by lesscrystalline carbon blacks. That is, both insufficient and too muchgraphitization fail to provide the thermal conductivity benefitsdemonstrated by carbon blacks according to the embodiments disclosedherein.

Polymer compositions included both cured polymers and pre-polymercompositions. As used herein, a “polymer” or “polymer matrix” is theform of a polymer composition after it has been polymerized and may besuitable for use as a masterbatch, compound or otherwise to manufacturearticles, for example, plastic articles As used herein, a “pre-polymer”is a polymer composition consisting of monomers or oligomers that havenot yet been polymerized. The polymers may be polymers that are cured bymethods known to those of skill in the art including heat, radiation,solvent evaporation, chemical catalysis or vulcanization. The polymersmay be based on one, two, three or multi part pre-polymer systems. A“polymer composite” or “polymeric composite” is a material that includesat least one polymer and a second distinct component. The secondcomponent of the composite can be particles, fibers, pigments or asecond polymer where the second polymer is distinct and not homogenouslymixed with the first polymer.

In some embodiments, the polymer(s) can be a thermoplastic polymer or athermosetting polymer. The polymer system can be a plastic. Theseplastic systems can be selected from those that are molded, extruded,coated, rolled or otherwise shaped into polymeric components. Further,the polymer group can be a homopolymer, copolymer, terpolymer, and/or apolymer containing one, two, three or more different repeating units.Further, the polymer group can be any type of polymer group, such as arandom polymer, alternating polymer, graft polymer, block polymer,star-like polymer, and/or comb-like polymer. The polymer group can alsobe one or more polyblends. The polymer group can be an interpenetratingpolymer network (IPN); simultaneous interpenetrating polymer network(SIN); or interpenetrating elastomeric network (IEN).

Specific examples of polymers include, but are not limited to,linear-high polymers such as polyethylene, poly(vinylchloride),polyisobutylene, polystyrene, polycaprolactam (nylon), polyisoprene, andthe like. Other general classes of polymers suitable for use includepolyamides, polycarbonates, polyelectrolytes, polyesters, polyethers,epoxies, polyanhydrides, (polyhydroxy)benzenes, polyimides, polymerscontaining sulfur (such as polysulfides, (polyphenylene) sulfide, andpolysulfones), polyolefins, polymethylbenzenes, polystyrene and styrenecopolymers (ABS included), acetal polymers, acrylic polymers,acrylonitrile polymers and copolymers, polyolefins containing halogen(such as polyvinyl chloride and polyvinylidene chloride),fluoropolymers, ionomeric polymers, polymers containing ketone group(s),liquid crystal polymers, polyamide-imides, polymers containing olefinicdouble bond(s) (such as polybutadiene and polydicyclopentadiene),polyolefin copolymers, polyphenylene oxides, polysiloxanes, poly(vinylalcohols), polyurethanes, thermoplastic elastomers, and the like. Insome embodiments, the polymer is a polyolefin, a polyurethane, apolystyrenic, a polyacrylate, a polyamide, a polyester, or mixturesthereof. Particularly suitable polymers include polyolefins andpolyamides.

In certain embodiments the polymer can be, for example, a polyolefin, avinylhalide polymer, a vinylidene halide polymer, a perfluorinatedpolymer, a styrene polymer, an amide polymer, a polycarbonate, apolyester, a polyphenyleneoxide, a polyphenylene ether, a polyketone, apolyacetal, a vinyl alcohol polymer, or a polyurethane. Useful polymersor resins include PET or polyethylene terephthalate, polystyrene, PBT orpolybutylene terephthalate and PBT alloys, polypropylene, polyurethane,styrene-acrylonitrile copolymer, ABS or acrylonitrile-butadiene-styreneterpoloymer, PVC or polyvinyl chloride, polyesters, polycarbonates,PP/PS or polypropylene polystyrene alloys, nylon, polyacetal, SAN orstyrene acrylonitrile, acrylics, cellulosics, polycarbonate alloys andPP or propylene alloys. Other combinations of these materials may beused.

Various polymers can be combined with partially crystallized carbonblacks to form composite polymers. The composite polymers may includethermoplastic polyolefins (TPO), polyethylene (PE, such as linear lowdensity (LLDPE), low density (LDPE), medium density (MDPE), high density(HDPE), ultra-high molecular weight (UHMWPE), very low densitypolyethylene (VLDPE), metallocene and medium density polyethylene(mLLDPE), polypropylene, copolymers of polypropylene, ethylene propylenerubber (EPR), ethylene propylene diene terpolymers (such as EPDM),acrylonitrile butadiene styrene (ABS), acrylonitrile EPDM styrene (AES),styrene-butadiene-styrene (SBS), polyoxymethylene (POM), polyamides (PA,such as PA6, PA66, PA11, PA12, and PA46), polyvinylchloride (PVC),tetraethylene hexapropylene vinylidenefluoride polymers (THV),perfluoroalkoxy polymers (PFA), polyhexafluoropropylene (HFP),polyketones (PK), ethylene vinyl alcohol (EVOH), copolyesters,polyurethanes (PU), thermoplastic polyurethanes, polystyrene (PS),polycarbonate (PC), polybutylene terephthalate (PBT), polyethyleneterephthalate (PET), polypheneylene oxide (PPO), and polyphenylene ether(PPE). Specific blends include PC/ABS, PC/PBT, PP/EPDM, PP/EPR, PP/PE,PA/PPO, and PPO/PE. The polymer compositions can be optimized to attainthe desired overall properties, such as jetness, conductivity,toughness, stiffness, smoothness, and tensile properties. The foregoinglist is not meant to be exhaustive but only illustrative of the variousmaterials that can be used. Blends of polymers containing one or more ofthese polymeric materials, where the described polymers are presenteither as the major component or the minor component, may also be used.The specific type of polymer can depend on the desired application.Specific examples of polymers are described in more detail below.

Generally, the polymeric groups described in Volume 18 of theEncyclopedia of Chemical Technology, KIRK-OTHMER, (1982), page 328 topage 887, and Modern Plastics Encyclopedia '98, pages B-3 to B-210, and“Polymers: Structure and Properties,” by C. A. Daniels, TechnomicPublishing Co., Lancaster, Pa. (1989), all incorporated in theirentirety herein by reference, can be used as the polymer(s). Thepolymers can be prepared in a number of ways and such ways are known tothose skilled in the art. The above referenced KIRK-OTHMER section,Modern Plastics Encyclopedia, and C. A. Daniels' reference providemethods in which these polymers can be prepared.

The polymer compositions of the present disclosure may also includesuitable additives for their known purposes and amounts. For example,the compositions may also include such additives as crosslinking agents,vulcanizing agents, stabilizers, pigments, dyes, colorants, metaldeactivators, oil extenders, lubricants, and/or inorganic fillers, andthe like, along with other additives discussed elsewhere herein. In someembodiments, the composites may also include additional particulatesdesigned to increase thermal conductivity. In many embodiments, carbonblack is the only particulate matter included, and the polymer compositemay be void of any other particulate matter. In some embodiments, thecarbon black can comprise greater than 50 wt %, greater than 75 wt % orgreater than 95 wt % of the particulate material in the polymercomposite.

The polymer compositions can be prepared using conventional techniquessuch as mixing the various components together using commerciallyavailable mixers. The composition may be prepared by batch or continuousmixing processes such as those well known in the art. For example,equipment such as discontinuous internal mixers, continuous internalmixers, reciprocating single screw extruder, twin and single screwextruder, etc. may be used to mix the ingredients of the formulations.Carbon black may be added to one or more of the components of amultipart polymer system and may be incorporated in the same or indifferent concentrations in each of the components. For example, in atwo part epoxy system, carbon black can be mixed into the epoxy resin,into the crosslinking agent, or into both. For copolymers andterpolymers, the partially crystallized carbon black can be incorporatedinto one, some, or all of the prepolymer components. The concentrationof partially crystallized carbon black in each component can, in someinstances, be varied to help match the viscosities of the differentcomponents or otherwise improve the mixing of the components. Partiallycrystallized carbon black may also be used in a polymer blend. As usedherein, a polymer blend is a homogeneous mixture of two or more distinctpolymers, and is different from a copolymer or terpolymer. Partiallycrystallized carbon blacks can be introduced directly into a polymerblend prior to curing or may be introduced into one or more of thepolymer precursors prior to blending with a second polymer precursor.Partially crystallized carbon blacks may also be incorporated into amasterbatch that is used as a carrier for subsequent mixing into asimilar or different polymer system prior to curing. In a masterbatch,the concentration of the partially crystallized carbon black may beconsiderably greater (e.g., at least 2×, at least 3×, at least 4×, orbetween 2× and 10×, for example, from 3× to 8× or from 2× to 6×) than inthe resulting composite polymer composition. The composite polymercompositions including partially crystallized carbon black may be mixedand formed into pellets for future use in manufacturing such materialsas articles for automotive applications.

Partially crystallized carbon blacks can be formed by increasing thecrystallinity of a base (untreated) carbon black (e.g., made by afurnace, thermal, lamp, plasma or acetylene decomposition process)without fully crystallizing the particles. Base furnace blacks exhibit anative crystallinity having a typical Raman microcrystalline planar size(L_(a)) in the range of 16 to 21 Å. In one set of embodiments, basecarbon blacks are partially crystallized by controlled heat treatment ofa base carbon black. A carbon black is “heat treated or processed” or“thermally treated or processed” if it is exposed to a secondary (afterinitial particle production) thermal process that alters thecrystallinity, surface energy and the morphology of the carbon blackparticle. Crystallization of the carbon black particles can also alterthe shape of the primary particle, for example, changing it fromsubstantially spherical to a more (but not necessarily perfect)polyhedral shape.

Partially crystallized carbon blacks can be formed from base carbonblacks that are readily available. Suitable base carbon blacks that canbe employed include: VULCAN® XC72, VULCAN® XC72R, and VULCAN® XC500carbon blacks and other carbon blacks sold under the Regal®, BlackPearls®, Spheron®, CSX™, Vulcan ® and Sterling® names, all availablefrom Cabot Corporation. Other carbon blacks such as KETJEN® EC 300 andKETJEN®EC 600 carbon blacks, supplied by AkzoNobel; PRINTEX® XE carbonblack, supplied by Evonik; Ensaco® 350 carbon black, supplied by TIMCAL;Raven®, XT Technology, Ultra®, and other carbon blacks available fromBirla Carbon; the Corax®, Durex®, Ecorax®, Sable™ and Purex® trademarksand the CK line available from Orion Engineered Carbons; S.A., andChezacarb® B carbon black supplied by Unipetrol RPA (Unipetrol Group)also can be utilized as base carbon blacks.

One measure of crystallinity is the Raman microcrystalline planar size.Raman measurements of L_(a) (microcrystalline planar size) are based onGruber et al., “Raman Studies of Heat-Treated Carbon Blacks,” CarbonVol. 32 (7), pp. 1377 1382, 1994, which is incorporated herein byreference. The Raman spectrum of carbon includes two major “resonance”bands at about 1340 cm⁻¹ and 1580 cm⁻¹, denoted as the “D” and “G”bands, respectively. It is generally considered that the D band isattributed to disordered sp² carbon and the G band to graphitic or“ordered” sp² carbon. Using an empirical approach, the ratio of the G/Dbands and the L_(a) measured by X-ray diffraction (XRD) are highlycorrelated, and regression analysis gives the empirical relationship:

L _(a)=43.5×(area of G band/area of D band)

in which L_(a) is calculated in Angstroms. Thus, a higher L_(a) valuecorresponds to a more ordered crystalline structure. Crystallinity canalso be measured by X-ray diffraction (XRD).

In one method of production, a heat treated carbon black can be preparedin a tube furnace or other suitable heater. The furnace can be heatedelectrically or by fossil fuel combustion. The temperature of the carbonblack bed can be consistent throughout to assure that all of the carbonblack is exposed to the same reaction conditions. The carbon black bedmay be static or may be a fluidized bed. The samples can be exposed tospecific temperatures, for example as provided below, for an amount oftime sufficient to reach, but not exceed, the desired partialcrystallinity. The samples can be thermally treated in an inertenvironment and an inert gas such as nitrogen may be passed through orover the carbon black to aid in removal of any volatiles that are lostfrom the carbon black. By sampling at various time intervals, anoperator can analyze the samples and accurately determine the carbonblack's level of crystallinity. Those of skill in the art are able tosample the carbon black after such a treatment, analyze the Ramanmicrocrystallinity, and adjust the process accordingly to achieve atarget level of, for example, crystallinity or surface energy. Once timeand temperature profiles are determined for a specific base carbonblack, the profile can be repeated on that specific base carbon black toreproduce partially crystallized carbon blacks having, for instance,desired crystallinity, surface energy, surface area and OAN structure.Other methods of heat treatment are known to those of skill in the artand may be calibrated in the same manner.

In various embodiments, carbon black particles may be exposed totemperatures of greater than or equal to 600° C., greater than or equalto 700° C., greater than or equal to 800° C., greater than or equal to1000° C., greater than or equal to 1100° C., greater than or equal to1200° C., greater than or equal to 1300° C., greater than or equal to1400° C., greater than or equal to 1500° C. or greater than or equal to1600° C. In other embodiments, carbon black particles may be exposed totemperatures of less than 600° C., less than 800° C., less than 1000°C., less than 1100° C., less than 1200° C., less than 1300° C., lessthan 1400° C., less than 1500° C., less than 1600° C., less than 1700°C. or less than 1800° C. Specific temperature ranges for treatmentinclude 1000° C. to 1800° C., 1100° C. to 1700° C., 1100° C. to 1600°C., 1100° C. to 1500° C., 1100° C. to 1400° C. and 1100° C. to 1300° C.The treatment can occur in an inert atmosphere such as nitrogen. Thedwell time of the material at the selected temperature may be as shortas milliseconds or greater than or equal to 30 minutes, one hour, twohours or more than two hours. In some embodiments, the dwell time may belimited to less than ten hours, less than three hours, less than twohours, less than 90 minutes, less than one hour or less than 30 minutes.The temperature may be kept constant or in alternative embodiments maybe ramped up or down during the dwell time.

In some embodiments, the partially crystallized carbon black may have aRaman microcrystalline planar size (L_(a)) of at least 20 Å, at least 23Å, at least 24 Å, at least 25 Å, at least 26 Å, at least 27 Å, at least28 Å, at least 29 Å, at least 30 Å, at least 35 Å or at least 40 Å. Insome cases, the partially crystallized carbon black has a Ramanmicrocrystalline planar size (L_(a)) of 100 Å or less, 75 Å or less, 50Å or less, 40 Å or less, 35 Å or less or 30 Å or less. Crystallinity,measured by Raman spectroscopy, may also be reported using the percentcrystallinity of the particle and in some cases, the percentcrystallinity may be greater than 25, greater than 30, greater than 35,greater than 37, greater than 40, greater than 42 or greater than 50.The same, or different examples, may exhibit a percent crystallinity ofless than 65, less than 60, less than 55, less than 50, less than 45,less than 42, less than 40, less than 38, less than 35, less than 32 orless than 27.

Partial crystallization can include increasing the native Ramanmicrocrystalline planar size of the base carbon black by greater than orequal to 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22 or 24 Å, and/orincreasing the native Raman microcrystalline planar size by less than orequal to 35, 30, 25, 20, 15 or 10 Å. Similarly, the native Ramanmicrocrystalline planar size of the base carbon black can be increasedby greater than or equal to 10%, 20%, 30%, 50%, 75%, 100%, 120% or 150%.In some embodiments the increase in the Raman microcrystalline planarsize of the base carbon black can be limited to less than or equal to10%, 20%, 30%, 50%, 75%, 100%, 120% or 150%. The amount ofcrystallization can be checked by pulling carbon black samples atvarious time intervals and measuring the Raman microcrystalline planarsize.

The treatment of the base carbon black can increase the Ramanmicrocrystalline planar size (L_(a)) by greater than 5, 10, 15, 20 or 25Å and decrease the surface energy while limiting a decrease in theBrunauer-Emmett-Teller (BET) surface area to no more than 25%, e.g., byno more than 10%, or decreases by 1% to 25%, 5% to 25%, 10% to 25%, 1%to 10%, or 5% to 10%, relative to the BET surface area of the basecarbon black. Similarly, OAN structure can be preserved so that thepartially crystallized carbon black has an OAN structure that is reducedby less than 5%, 10% or 25% when compared to the base carbon black.

The surface energy (SE) of a carbon black particle can be determined bymeasuring the water vapor adsorption using a gravimetric instrument. Thecarbon black sample is loaded onto a microbalance in a humidity chamberand allowed to equilibrate at a series of step changes in relativehumidity. The change in mass is recorded. The equilibrium mass increaseas a function of relative humidity is used to generate the vaporadsorption isotherm. Spreading pressure (in mJ/m²) for a sample iscalculated as π_(e)/BET, in which:

π_(e) = RT∫₀^(p0)Γdln p

and R is the ideal gas constant, T is temperature, Γ is moles of wateradsorbed, p0 is the vapor pressure, and p is the partial pressure of thevapor at each incremental step. The spreading pressure is related to thesurface energy of the solid and is indicative of thehydrophobic/hydrophilic properties of the solid, with a lower surfaceenergy (SE) corresponding to a higher hydrophobicity.

In some embodiments, the partially crystallized carbon black has asurface energy (SE) of 10 mJ/m² or less, 9 mJ/m² or less, 8 mJ/m² orless, 7 mJ/m² or less, 6 mJ/m² or less, 5 mJ/m² or less, or 3 mJ/m² orless. In the same and other embodiments, the partially crystallizedcarbon black has a surface energy (SE) of greater than 0 mJ/m², greaterthan 1 mJ/m², greater than 2 mJ/m², greater than 3 mJ/m², greater than 4mJ/m², greater than 5 mJ/m², greater than 6 mJ/m², greater than 7 mJ/m²,greater than 8 mJ/m² or greater than 9 mJ/m².

One way of measuring the surface area of carbon blacks is theBrunauer-Emmett-Teller method (BET by ASTM 6556). Different embodimentsof the partially crystallized carbon blacks used herein may have a BETsurface area of at least 100 m²/g, e.g., ranging from 100 m²/g to 600m²/g. In other cases, the partially crystallized carbon black has a BETof at least 200 m²/g, at least 300 m²/g, at least 400 m²/g, at least 500m²/g or at least 600 m²/g. In some embodiments, the BET of the partiallycrystallized carbon black is less than 1200 m²/g, less than 1000 m²/g,less than 800 m²/g, less than 700 m²/g, less than 600 m²/g or less than500 m²/g. In one particular set of embodiments, the BET surface area maybe in the range of 40 to 400 m²/g, 46 to 350 m²/g, 40 to 300 m²/g, or 40to 200 m²/g. In another embodiment, the BET surface area is less than425 +/−25 m²/g.

Another way of characterizing the surface areas of carbon blacks is touse the statistical thickness surface area (STSA according to ASTMD6556). The STSA of many of the carbon blacks described herein can be atleast 100 m²/g, e.g., ranging from 100 m²/g to 600 m²/g. In other cases,the partially crystallized carbon black has an STSA of at least 200m²/g, at least 300 m²/g, at least 400 m²/g, at least 500 m²/g or atleast 600 m²/g. In some embodiments, the STSA of the partiallycrystallized carbon black is less than 1200 m²/g, less than 1000 m²/g,less than 800 m²/g, less than 700 m²/g, less than 600 m²/g or less than500 m²/g.

While thermal treatment is one method to provide for partialcrystallization, specific temperatures, dwell times and furnacegeometries may need to be adjusted to arrive at desired levels ofcrystallinity, structure, surface area and surface energy. For example,it has been found that a partially crystallized carbon black prepared byheating a base carbon black at a temperature ranging from 1100° C. to1800° C. for a limited time (e.g., less than 10 hours, less than 2 hoursor less than 1 hour) can yield a thermally-treated carbon black havingBET surface area (ASTM 6556) ranging from 100 m²/g to 1100 m²/g and oneor more other specific properties, such as a surface energy (SE) of 10mJ/m² or less (e.g., 9 mJ/m²or less, 6 mJ/m²or less, or 3 mJ/m² orless), a Raman microcrystalline planar size (L_(a)) of at least 22 Å andless than 60 Å (e.g., ranging from 22 Å to 60 Å, at least 25 Å, orranging from 25 Å to 50 Å etc.) or a combination thereof.

In many embodiments, the structure of the partially crystallized carbonblacks may be controlled within a specific range. Structure can bemeasured using the oil absorption number (OAN) which is known to thoseof skill in the art and is described in ASTM D2414. For example, the OANmay be greater than greater than 120 cm³/100 g, greater than 140 cm³/100g, or greater than 160 cm³/100 g. In other embodiments, the OAN may beless than 200, less than 180 or less than 160 cm³/100 g. In a set ofembodiments, the OAN may be greater than 120 cm³/100 g and less than 200cm³/100 g. Experimental data show that if the OAN of the base carbonblack is too low, then partial crystallization does not provideimprovements to thermal conductivity.

In one thermal treatment embodiment, the base carbon black prior topartial crystallization (base carbon black) has a surface energy ofgreater than 10 mJ/m² and a BET surface area (ASTM 6556) of at least 50m²/g. For example, the BET surface area can be at least 100 m²/g, 200m²/g, 300 m²/g, at least 500 m²/g, at least 1000 m²/g, 1200 m²/g, atleast 1300 m²/g, at least 1400 m²/g, or at least 1500 m²/g. In the sameor different embodiments, the BET surface area can be less than or equalto 150 m²/g, 300 m²/g, 500 m²/g, 1000 m²/g, 1500 m²/g or 2100 m²/g. Thebase carbon black can, in some cases, have a surface energy of greaterthan 10 mJ/m² and a BET surface area ranging from 200 m²/g to 1500 m²/g,e.g., a BET surface area ranging from 300 m²/g to 1500 m²/g, from 500m²/g to 1500 m²/g, from 1000 m²/g to 1500 m²/g, from 300 m²/g to 1000m²/g, from 500 m²/g to 1000 m²/g, from 300 m²/g to 500 m²/g, or from 200m²/g to 500 m²/g. These same ranges of BET surface areas can bemaintained in partially crystallized carbon blacks made from these basecarbon blacks although the surface energy will typically be lower thanin the base carbon black. The base carbon black can be a furnace black.

In a specific set of examples, the partially crystallized carbon blackhas a BET surface area of 125-175 m²/g, e.g, within the range of fromabout 138 to 169 m²/g, for example 130, 135, 138, 142, 147, 150, 155,160, 165 or 169 m²/g; an external surface area (STSA) within the rangeof from 135 to 142 m²/g, for example, 136, 137, 138, 139, 140 or 141m²/g; a total pore volume of 0.44 to 0.49 ml/g, for example, 0.45. 0.46,0.47 or 0.48 ml/g; Raman crystallinity (L_(a)) of from 28.4 to 34.6 Å,for example, 29.0, 29.5, 30.0, 30.5, 31.0, 31.5, 32.0, 32.5, 33.0, 33.5or 34.0 Å; and a surface energy (SE) of 4.9 to 6.3 mJ/m², for example,5.2, 5.5, 5.8 or 6.1 mJ/m².

The iodine number according to ASTM D1510 of the partially crystallizedcarbon blacks may be, for example, less than 450, less than 425, lessthan 400, less than 350, less than 300, less than 250 or less than 200mg/g. In the same or other embodiments, the iodine number may be greaterthan 50, greater than 100, greater than 150, greater than 200, greaterthan 250 or greater than 300 mg/g.

The partially crystallized carbon blacks described herein are typicallyunmodified, meaning they are void of any organic treatment. As usedherein, a carbon black that is unmodified is a carbon black that has nothad organic groups chemically attached to it.

Carbon black can be provided in any amount suitable for the polymersystem being utilized, the specific end use, mixing technique,viscosities encountered, desired properties of the finished product, andother considerations. Partially crystallized carbon black can be presentin the system in a total concentration within the general range of fromabout 12% to about 28% by weight, preferably 15-25% by weight, forexample 12% to 20%, 15% to 23%, or 17% to 28%. Other loading levels canbe used, as determined by routine experiments. Too high a loading levelwill cause the resulting polymer composition to be too viscous to forminto articles; too low a loading level will not provide sufficientthermal conductivity. It is understood that the total amount of carbonblack can be added to one component only or can be divided between oramong some or all components that make up the polymer system beingemployed. Mixtures of two, three or more different carbon blacks canalso be used.

The partially crystallized carbon blacks described herein can provideimproved thermal conductivity as well as improved rheology when comparedto the corresponding base carbon black in the same polymer system. Forexample, the use of partially crystallized carbon blacks in polymerprecursors can allow for high loadings without an increase in viscosityor, alternatively, can allow for similar loadings and a lower viscosity.When used in polymer systems at concentrations of, for example, 12 to 28percent by weight, the partially crystallized carbon blacks, whencompared to the corresponding base carbon black exhibiting Ramanmicrocrystallinity (L_(a)) of less than 21 Å, can improve thermalconductivity by more than 5, 10, 15 or 20 percent in comparison to thecorresponding base black. At the same concentrations, the thermalconductivity may be improved by more than 1.6× with respect to thevirgin polymer, for example, from 1.7× to 3× or from 2× to 4× withrespect to the virgin polymer. At the same concentrations, the melt flowindex (MFI) of the polymer precursor can be improved by more than 50%,100% or 150%. These improvements in thermal conductivity and viscositycan be exploited individually or in tandem. For example, a one to onesubstitution of partially crystallized carbon black for a base carbonblack can provide a polymer composition that exhibits both improvedviscosity and improved thermal conductivity. Alternatively, thesubstitution of partially crystallized carbon black for a base carbonblack means the amount of carbon black added to the polymer compositioncan be increased without any loss in flow properties but with asubstantial gain in thermal conductivity due to both a more efficienttransfer of heat per gram of carbon black and the higher loading ofcarbon black in the composition. In another aspect, the use of apartially crystallized carbon black in a polymer composition allows forthe use of a reduced amount of carbon black without any loss of thermalconductivity in the polymer composition.

In some embodiments, the polymer system consists of, or essentially of,a polymer and partially crystallized carbon black. In other embodiments,the polymeric component of the composite polymer composite accounts forgreater than 50%, greater than 75% or greater than 85% of the polymericsystem by weight. In another embodiment, the polymer system consists of,or essentially of, a polymer, a partially crystallized carbon black, andboron nitride (BN).

Ingredients other than carbon black and the polymeric component can bepresent in the polymer described herein and/or utilized in itspreparation. The nature, amounts and/or proportions of these ingredients(also referred to as “additives”) typically depend on the polymer systemutilized, end use, processing conditions, properties, e.g., viscosity ofthe precursor formulation, and other considerations. In many cases,additives are provided as part of the polymer system utilized and/or canbe added at a suitable point during the formulation process, prior to orduring curing or at another suitable time. Amounts often are preset bythe polymer system selected. This is particularly true with off theshelf systems. In other cases, suitable additive amounts can bedetermined based on experience and/or by routine experimentation.Examples of additional ingredients include but are not limited to curingagents, rheology modifiers, waxes, reactive diluents, extenders,pigments, fillers, catalysts, UV and thermal stabilizers, adhesionpromoters, such as silanes, surfactants, tackifying agents, solvents andothers, including other additives discussed elsewhere herein.

In some embodiments, the composition can include a second species ofparticle to promote heat transfer. For instance, in addition to apartially crystallized carbon black, the composition may include a highthermal conductivity (HTC) particle. HTC particles includenon-electrically conductive materials such as ceramics like aluminumnitride (AlN), beryllium oxide, silicon carbide and boron nitride (BN).Electrically conductive HTC particles include metals from the periodictable such as molybdenum, aluminum, copper, tungsten, silver and gold.Other HTC particles may comprise minerals such as diamond, corundum,hematite, spinel and pyrite. The specific shape of an HTC particle canimprove heat transfer, and particles may be in the form of spheres,cylinders (rods), cubes, blades or platelets. HTC particles can also beirregularly shaped. In certain embodiments, these HTC particles includenon-carbonaceous particles that exhibit a thermal conductivity ofgreater than 30 W/mK. Specific examples of HTC particles that may beused in conjunction with partially crystallized carbon blacks includeBN, MgO, ZnO, and Al₃O₂. In some cases, the combination of an HTCparticle such as BN and a partially crystallized carbon black has beenshown to provide more efficient heat transfer than a total equivalentloading (by mass or volume) of BN only. For example, the combination ofan HTC particle such as BN and a partially crystallized carbon black canincrease the thermal conductivity of a polymer composition by 1.5×, 2×,3×, 4× or more, for example, from 1.5× to 6× or from 2× to 4×, comparedto the same polymer composition absent the BN and partially crystallizedcarbon black.

To form the composite polymers and polymer precursors described herein,components are combined using a suitable mixing technique and in asuitable sequence, including simultaneous mixing of some or all of thestarting materials.

As used herein, a polymeric precursor is a monomer or oligomer that isnot yet polymerized but is capable of being made into a polymer throughcross-linking or other polymerizing process. The polymeric precursorsused herein to form carbon black composites are fluid enough that carbonblack can be evenly dispersed throughout the precursor. In one example,a partially crystallized carbon black is combined with a polymericprecursor such as a polymeric precursor of a thermoset. Under suitableconditions (e.g., specific temperatures, pressures, curing time,presence of curing agents, and/or other parameters), the polymericprecursor is cured (polymerized), as known in the art. The precursor canbe the entire polymer system utilized to form the conductive materialsdescribed herein or a component thereof. The partially crystallizedcarbon black, in various embodiments, can be dispersed in aggregate oragglomerate form.

In multi-component systems (i.e., systems made of two or morecomponents), the total amount of carbon black can be divided between oramong some or all of the components. Ratios of the amounts in eachcomponent can depend, for example, on the relative volumes of thecomponents. In some multi-part systems, attempts are often made to matchthe viscosities of the components, in order to facilitate processing,e.g., mixing. In such cases, carbon black can be added to two or moreprecursor components in amounts selected to yield similar viscosities.Such amounts can be established based on the formulator's experience ordetermined by routine experimentation.

Ratios of carbon black in each polymer precursor component also candepend on factors such as the nature of the curative used, desiredcuring time, properties of the final product and so forth, as known inthe art. The weight ratios of carbon black to polymer precursor can be,for example, from 1:1 to 1:10, for example, from 1:2 to 1:8 or from 1:4to 1:6. Other suitable ratios can be selected. In an exemplary two-partformulation, carbon black is added to both components, with smaller(less than 50% by weight, e.g., less than 40%, less than 30%; or 25% orless, for instance within the range of from about 45% to about 15%; 40to about 20% or 35 to about 25% by weight) amounts typically added tothe cross-linking agent.

Various mixing techniques are known for mixing solid ingredients with apolymer precursor. For example, dry powder mixing can be employed withpolymer precursors that are in solid form. Depending on end use, theresulting mixture can be combined with a liquid to form a slurry orpaste.

With a precursor that presents a sufficiently low viscosity, however,mixing can be conveniently obtained by dispersing carbon black and,optionally, other additives in the precursor. In many cases, carbonblack and, optionally, other additives, are dispersed using suitablemixing equipment, such as, for instance, three-roll mills, sigma blademixers, high shear mixers, or others, as known in the art. The mixingoperation can be performed manually or by robotics.

Co-solvents and/or dispersants can be added to facilitate the process.In a specific embodiment, the dispersion is formed in the absence offurther co-solvents and/or dispersants, i.e., without adding co-solventsand/or dispersants that are not part of the initial formulation recipe.In other cases, using a carbon black such as described herein lowers theamounts of solvents and/or dispersants required in an original recipe(for instance, a recipe, for a formulation that uses untreated carbonblack).

The distribution of carbon black achieved in a mixture can be assessedby visual inspection or by a suitable qualitative or quantitativeanalytical technique. Uniform or substantially uniform distribution isthought to promote electrical conductivity, thermal conductivity,mechanical strength, and/or other properties of the end product.

In many cases a composition that includes carbon black and a polymerprecursor is viscoelastic, i.e., exhibits both viscous and elasticcharacteristics when undergoing deformation. Whereas under appliedstress viscous materials resist shear flow and strain linearly withtime, elastic materials strain when stretched and quickly return totheir original state once the stress is removed. Viscoelastic materialshave elements of both properties and show time-dependent strain.

Viscoelasticity is typically studied using dynamic mechanical analysis,applying a small oscillatory stress and measuring the resulting strain.While with purely elastic materials stress and strain are in phase, sothat the response of one caused by the other is immediate, strain lagsstress by a 90 degree phase lag in purely viscous materials.Viscoelastic materials are thought to exhibit an in-between behavior,showing some lag in strain.

The complex dynamic modulus, G, is generally used to represent therelationship between the oscillating stress and strain:

G=G′+iG″

where: the real part of the complex dynamic modulus, G′, is the storagemodulus; G″ of the imaginary part is the loss modulus; and i²=−1.

If σ₀ and ε₀ are the amplitudes of stress and strain, respectively, andδ is the phase shift between them, G′=(σ₀/ε₀)cos δ and G″=(σ₀/ε₀)sin δ.

Techniques related to conducting a Dynamic Mechanical Analysis (DMA) todetermine elastic modulus (or storage modulus, G′), viscous modulus (orloss modulus, G″) and damping coefficient (tan δ) as a function oftemperature, frequency or time are described, for example, in ASTMD4065, D4440 and D5279.

In many cases, combining carbon black or other solid ingredients with aviscoelastic composition tends to increase its storage modulus.Excessive increases, however, can render mixing and/or handling of thecomposition, including its application, difficult or impossible. Inpractice, this limits the amounts of carbon black that can be added andthus curtails the thermal conductivity and/or other effects sought byadding carbon black in the first place. It was discovered, however, thata carbon black such as the partially crystallized carbon blacksdescribed herein can mitigate increases in the storage modulus. Forexample, a partially crystallized carbon black added to a component of atwo part epoxy system can lower the storage modulus of the compositionby about one order of magnitude relative to a comparative formulationthat is identical (same ingredients and amounts) to the compositionexcept with respect to the carbon black which is a base carbon black.The lower viscosity achievable using partially crystallized carbonblacks enhances the rheological flexibility of the formulation.

Without wishing to be bound to any particular interpretation, it isbelieved that particle-polymer compatibility and particle-particlecohesive strength may both play a role in the dispersion of carbon blackin a polymer precursor. While the underlying architecture and morphologyof a base carbon black particle as compared to its partiallycrystallized form is essentially unchanged, it is thought that theuntreated and partially crystallized carbon blacks perform differentlywhen dispersed. Thus it is possible that the surface of the partiallycrystallized carbon particle is more compatible with the polymer(relative to the untreated carbon black), facilitating dispersion. Areduction in the particle-particle cohesive strength could also lead toan enhancement in dispersion. As a result, a polymer compositioncontaining partially crystallized carbon black can be formulated to amuch lower viscosity than one containing untreated carbon black. Theformulator can then have the flexibility to increase the loading ofcarbon black and/or that of other additives. In another approach, themixing, handling and/or application of the lower viscosity composition(at an unchanged loading) can facilitate its use.

The viscoelastic composition can be applied for a desired end use, forexample to a substrate, employing techniques known in the art.Application of the viscoelastic composition can be manual or automatedand can be performed by extrusion, painting, spraying, brushing,dipping, or by another suitable method. In other cases, the compositionis molded or extruded.

To produce a thermally conductive polymer, the composition containingcarbon black is cured under suitable conditions (temperature, rampingand soaking protocols, time period, pressure, radiation, specific curingaids, special atmospheres if necessary, etc.) as known in the art or asdetermined by experience with similar formulations and/or routineexperimentation. With commercial systems, for example, curing typicallyis conducted according to instructions provided by the manufacturer. Asknown in the art, curing conditions are highly dependent on the specificpolymer system employed, heat curing being a common requirement.

Curing the polymer(s) in the polymer system produces a thermallyconductive material that can be thought of as a polymer-carbon blackcomposite. In many embodiments, the material displays good thermalconductivity as well as good mechanical and rheological properties.

EXAMPLES Example 1—Viscosity

To evaluate the rheological effects of using partially crystallizedcarbon blacks in a polymer precursor, several polymer precursor sampleswere prepared using both base and partially crystallized carbon blacks.These included high density polyethylene (HDPE), polystyrene (PS),polycarbonate (PC) and polyamide-6 (PA). Each of the carbon blacks isidentified in Table 1. The carbon blacks were heat treated under aninert atmosphere at the temperature given in the table until theyachieved the Raman La specified in Table 2. The analyzed properties foreach of the carbon blacks are reported in Table 2. The indicator “NA”means that the value was not measured and “ND” means that the value wasbelow the limit of detection. Iodine number was determined according toASTM D1510; BET surface area was determined according to ASTM D6556; OANstructure was determined according to ASTM 2414; and surface energy(SE), Raman crystallinity (L_(a)) and percent crystallinity weredetermined according to the methods described above. Melt Flow Index ofthe polymer composites was measured at the reported loads andtemperatures according to ISO1133.

The HDPE resin was Lupolen™ 4261A IM resin from LyondellBasell andexhibits an MFI of 15 g/10 min at a load of 2.16 kg and a temperature of190° C. Melt flow index (MFI) for the composite HDPE samples wasmeasured at 21.6 kg and 190° C. for 10 min. A 1.664 L internal batchBanbury mixer was used to mix in the carbon black under the followingconditions:

Chamber cooling temperature: 40° C. Rotor cooling temperature: 40° C.Mixing time post flux: 90 s Ram pressure: 4.2 bars Rotor speed: 180 RPM

The polystyrene (PS) resin was Edistir™ N1840 resin from Polimeri. Ithas an MFI of 10 g/10 min at a load of 5 kg at 200° C. Melt flow index(MFI) for the composite PS samples was measured at 10 kg and 200° C. for10 min. A 1.664 L internal batch Banbury mixer was used to mix in thecarbon black under the following conditions:

Chamber cooling temperature: 20° C. Rotor cooling temperature: 20° C.Mixing time post flux: 90 s Ram pressure: 4.2 bars Rotor speed: 180 RPM

The polycarbonate (PC) resin was Wonderlite™ PC-122 resin from ChimeiAsahi. It has an MFI of 22 g/10 min at a load of 1.2 kg at 300° C. Meltflow index for the composite PC samples was measured at 10 kg and 260°C. for 10 min. The polycarbonate polymers were prepared on an APV twinscrew extruder with a moderate shear screw profile under the followingconditions:

Screw Speed: 300 RPM Output: 12 kg/h Temperature from 175-230-230-260-hopper to die (° C.): 260-260-260-240

The polyamide-6 (PA) was Zytel™ ST7301NC resin from Dupont. Melt flowindex (MFI) for the composite PA samples was measured at 10 kg and 275°C. for 10 min. The PA polymers were prepared on an APV twin screwextruder with a moderate shear screw profile under the followingconditions:

Screw Speed: 300 RPM Output: 12 kg/h Temperature from 175-230-230-260-hopper to die (° C.): 260-260-260-240

Melt flow index results for each of the polymer composites are providedin Table 3 and indicate that at the same loading, the composite samplesincluding partially crystallized carbon black provided significantlyhigher MFI than did the parent, or base carbon black, from which theywere formed. It is notable that these improvements are obtained withoutsignificantly altering the surface area or structure of the carbonblacks.

TABLE 1 Carbon Black Sample Identification Sample ID Base Carbon BlackTreatment CB1 VULCAN XC500 Untreated CB2 VULCAN XC500 Thermally treatedat 1200° C. CB3 VULCAN XC72 Untreated CB4 VULCAN XC72 Thermally treatedat 1200° C. CB5 VULCAN XC200 Untreated CB6 VULCAN XC200 Thermallytreated at 1400° C. CB7 VULCAN XC68 Untreated CB8 VULCAN XC68 Thermallytreated at 1050° C. CB9 REGAL 85 Untreated CB10 REGAL 85 Thermallytreated at 1200° C. CB11 CSX 99 Untreated CB12 CSX 99 Thermally treatedat 1400° C. CB13 VULCAN XC500 Thermally treated at 1800° C. CB14 VULCANXC72 Thermally treated at 1400° C. CB15 VULCAN XC72 Thermally treated at1500° C. CB16 CSX 691 Untreated

TABLE 2 Carbon Black Properties Crystal- I₂ No. BET OAN SE linity Sample(mg/g) (m²/g) (cm³/100 g) (mJ/m²) L_(a) (Å) % CB1 73.3 57 148.0 18.0 2133 CB2 71.1 55 139.5 1.0 38 47 CB3 252.7 235 175.4 14.9 18 29 CB4 177.8153 164.5 6.3 39.5 47.6 CB5 46 46 115 2.6 18 29 CB6 NA 46 115 NA 29 40CB7 68 58 123 9.3 18.4 29.7 CB8 NA NA NA <1 29.2 40.2 CB9 16 NA 36 13.617 28 CB10 16 NA 36 NA 32 42 CB11 NA 425+/−25 150 16.2 20 31 CB12 NA425+/−25 150 NA 24 36 CB13 74 NA 148 ND 95 68 CB14 NA NA NA 1.3 39.547.6 CB15 NA NA NA 0.9 41.6 48.9 CB16 15 20 95.2 14 18 29 NA = NotAvailable

TABLE 3 Melt Flow Index Loading MFI MFI MFI MFI Wt % HDPE PS PC PA CB118 8.3 CB2 18 11.9 CB1 24 5.5 11.8 15.9 CB2 24 8.6 13.4 21.6 CB1 26 11.6CB2 26 19.3 CB3 16 9.3 16.4 CB4 16 10.4 17.5 CB3 22 5.1 7.8 13.4 20.8CB4 22 7.2 9.2 31.3 23.4 CB3 24 8.9 CB4 24 24.5 CB7 22 5.6 CB8 22 9.2

Example 2—Thermal Conductivity Measurements

To evaluate the thermal conductivity (TC) of composite polymerscontaining partially crystallized carbon blacks, a series of HDPEcomposite samples was tested using a NETZSCH® LFA 467 light flashapparatus at 25° C. The samples included both base carbon blacks as wellas partially crystallized carbon blacks and the composite polymers wereproduced as described above in Example 1. Test samples for thermalconductivity measurements were molded using electrically heated pressesto make 2.54 cm discs. The mold was made with 316 stainless steel plateswith four one inch holes and 316 stainless steel cover plates. One gramof each sample was weighed out and placed in each round hole. KEVLAR®para-aramid sheets were placed on the top and bottom of each mold. Thepresses were set at 365° F., and the mold was placed on the presses fora 5 minute warm up, and then closed and pressurized to 23 psi for fiveminutes. The pressure was released by opening the presses, the hot moldswere removed and placed on water cooled presses for ten minutes.

The sample size for measurement was a circular disc, 25 mm in diameter,˜1 mm thickness. Specimen thickness was measured by taking the averageof three thickness values using a caliper measurement tool. Samples werecoated with a thin layer of graphite spray lubricant and allowed to dryprior to measurement. The samples were loaded into the sample holder andequilibrated at 25° C. for 4 minutes. After equilibration time, eachsample was pulsed with high-intensity, short duration radiant energyoriginating from a xenon lamp. The energy of the pulse was absorbed onthe front face of the specimen and an IR detector measured thetemperature rise on the rear face of the specimen. The thermaldiffusivity value was calculated from the measured sample thickness andthe time required for the temperature to reach a maximum value. Specificheat of each sample was calculated by measuring a standard referencematerial with a pre-established specific heat table (Pyroceram9XX) andusing the Proteus62 LFA Analysis software to calculate the experimentalvalues. Thermal conductivity was calculated by using equation 1.0:

k=ρ*c_p*α

Where k is the thermal conductivity (W/mK), ρ is the density of thesample (g/m³), cp is the specific heat capacity of the sample (J/g/K),and α is the thermal diffusivity of the sample (m²/s).

Thermal conductivity results are provided in Table 4 and FIGS. 1-5. FIG.1 is a bar graph showing the relative thermal conductivity provided byVULCAN XC500 type carbon black (CB1) and two of its partiallycrystallized derivatives, CB2 and CB13. The results for CB2 showsignificantly higher thermal conductivity than for the base carbonblack. Results for sample CB13, which was thermally treated at a highertemperature than CB2, exhibits thermal conductivity identical to that ofthe base carbon black CB1. It is believed that this poor thermalconductivity is the result of impaired particle dispersion due to overcrystallizing the carbon black as CB13 has a Raman L_(a) of 95 Å and apercent crystallinity of 68.

FIG. 2 is a bar graph showing the relative thermal conductivity providedby VULCAN XC72 type carbon black (CB3) and three of its partiallycrystallized derivatives. Each of the partially crystallizedderivatives, CB4, CB14 and CB15, show thermally conductivitysignificantly higher than that of the base carbon black, CB3. It isnotable that these three partially crystallized carbon blacks have RamanL_(a) measurements of 39.5, 39.5 and 41.6 Å, respectively.

FIG. 3 is a bar graph showing the relative thermal conductivity providedby VULCAN XC200 type carbon black (CB5) and its partially crystallizedderivative, CB6. CB6 provides much improved thermal conductivitycompared to its base carbon black (CB5) and has a Raman L_(a) of 29 Å(an increase of 11 Å).

FIG. 4 is a bar graph showing the relative thermal conductivity providedby REGAL 85 type carbon black (CB9) and its partially crystallizedderivative, CB10. The partially crystallized derivative shows identicalthermal conductivity to its base carbon black, CB9. Although partiallycrystallized, it is believed that thermal conductivity is not improvedover the base carbon black because of the low structure (OAN of 36cm³/100 g) of both the base carbon black (CB9) and the partiallycrystallized carbon black (CB10).

FIG. 5 is a bar graph showing the relative thermal conductivity providedby CSX 99 type carbon black (CB11) and its partially crystallizedderivative, CB12. The thermal conductivity of the partially crystallizedcarbon black is slightly below that of the base carbon black (CB11) fromwhich it is derived. Although CB12 was partially crystallized, it isbelieved that its poor thermal conductivity contribution was a result ofits relatively low Raman L_(a) of 24 Å.

In aggregate, these results show that the thermal conductivity ofpolymer composites can be significantly improved by substituting apartially crystallized carbon black for a base carbon black. These dataalso indicate that optimal thermal conductivity results are achievedwhen the Raman L_(a) is greater than 24 Å and less than 95 Å, and whenthe OAN structure of the partially crystallized black is greater than 36cm³/100 g.

As noted above, the partially crystallized carbon blacks are alsocapable of higher loadings than the base carbon blacks without adverselyaffecting the rheology of the polymer precursor. These higher loadingscan be combined with the higher thermal conductivity to provide polymercomposites having significantly higher thermal conductivity with no lossin rheological properties. Alternatively, lower carbon black loadingscould be used (than the base carbon blacks) without a loss in polymercomposite thermal conductivity.

TABLE 4 Thermal Conductivity of HDPE composites. Sample Concentration inThermal Conductivity ID HDPE (wt %) (W/mK) CB1 18.8 0.45 CB2 18.6 0.51CB3 20.2 0.38 CB4 16.7 0.48 CB5 21 0.37 CB6 21 0.44 CB9 21.1 0.39 CB1021.1 0.39 CB11 19.9 0.35 CB12 19.8 0.34 CB13 19.9 0.45 CB14 14.6 0.48CB15 15.4 0.51

Example 3—Thermal Conductivity Measurements

In another set of experiments, thermal conductivity was measured incomposite samples that were produced including two different types offiller. Results are provided below in Table 5. Filler concentrations areprovided as volume percent. All samples were compounded with the samepolyolefin resin, Lupolen 4261 A IM HDPE, available from Lyondell BasellIndustries. This polyolefin has a melt flow index of 15 g/10 min (@190°C. and 21.6 Kg). Sample “BN1” is grade PCTP30D boron nitride highthermal conductivity (HTC) particles available from Saint-Gobain. TheseBN particles are platelets having a D₅₀ of 180 μm, have not been heattreated and have a thermal conductivity (W/mK) of from 30-130, arefractive index of 1.74 and a dielectric constant of from 3 to 4. Eachcomposite was compounded as described below.

Molding Experimental Procedure

Each composite was compounded by mixing the particles and polymer resinwith a 60 cc Brabender mixer (0.7 fill ratio) at a temperature of 170°C. for 15 minutes at 35 rpm. Each batch was then removed from the mixingchamber and allowed to cool to room temperature. Once the mixturereached room temperature it was introduced into a Retsch SM300 grinderthat ran at 800 rpm to grind the polymer composite into a powder. Theresulting polymer composite powder was collected and compression moldedwith a heated press at 365° F. for five minutes. To facilitate the moldrelease step, Kevlar sheets were placed between the stainless steel moldand the polymer composite. The resulting polymer composite molds werethen placed on water cooled presses for ten minutes. The end result wasa set of 25 mm (diameter)/1 mm (thickness) discs suitable for thermalconductivity measurements.

Thermal Conductivity Experimental Procedure

All the samples were measured for thermal conductivity on a NETZSCHLFA467 thermal conductivity meter at 25° C. The sample size formeasurement was a circular disc, 25 mm in diameter, ˜1 mm thickness.Specimen thickness was measured by taking the average of three thicknessvalues from a caliper measurement tool. Samples were coated with a thinlayer of graphite spray lubricant and allowed to dry prior tomeasurement. Samples were then loaded into the instrument's sampleholder and equilibrated at 25° C. for 4 minutes. After equilibrationtime, each sample was pulsed with high-intensity, short duration radiantenergy originating from a xenon lamp. The energy of the pulse wasabsorbed on the front face of each specimen and an IR detector measuredthe temperature rise on the rear face of the specimen. The thermaldiffusivity value was calculated from the measured sample thickness andthe time required for the temperature to reach a maximum value. Thespecific heat of each sample was calculated by measuring a standardreference material with a pre-established specific heat table(Pyroceram9) and using the Proteus62 LFA Analysis software to calculatethe experimental values. Thermal conductivity was calculated by usingthe following equation:

k=ρ*c_p*α

Where k is the thermal conductivity (W/mK), ρ is the density of thesample (g/m³), cp is the specific heat capacity of the sample (J/gK),and α is the thermal diffusivity of the sample (m²/s). Results areprovided in Table 5, below.

TABLE 5 Volume Avg. TC Avg. ST. DEV Grade % [W/mK] [W/mK] CB1 10 0.3630.006 CB1 15 0.385 0.007 CB1 20 0.412 0.011 CB1 30 0.498 0.014 CB1 + BN1 20 BN1 0.580 0.066 2.5 CB1 CB1 + BN1  20 BN1 0.615 0.061   5 CB1 CB1 +BN1  20 BN1 0.708 0.023  10 CB1 CB16 +  20 BN1 0.546 0.020 BN1 2.5 CB2CB16 +  20 BN1 0.559 0.032 BN1   5 CB2 CB16 +  20 BN1 0.673 0.054 BN1 10 CB2 BN1 10 0.469 0.025 BN1 15 0.626 0.091 BN1 20 1.123 0.186 BN1 271.404 0.043 CB2 + BN1  20 BN1 1.208 0.073 2.5 CB2 CB2 + BN1  20 BN11.367 0.078   5 CB2 CB2 + BN1  20 BN1 1.599 0.092  10 CB2 CB2 10 0.4520.072 CB2 15 0.481 0.102 CB2 20 0.536 0.038 CB2 25 0.590 0.049 HDPE None0.289 0.020

FIG. 6 provides a graphical representation of the thermal conductivityof the composites including either only BN, only thermally treatedcarbon black, or only untreated carbon black. The results show theexcellent thermal transfer properties of BN but also indicate that thepartially crystallized carbon black (CB2) performs significantly betterthan its parent material CB1.

FIG. 7 adds in some of the composites that include two differentparticle types. The combination of CB1 and BN1 as well as thecombination of CB16 and BN1 are plotted. It can be seen from the plotthat the combination of these carbon blacks and the boron nitrideactually reduces the thermal conductivity when compared to BN by itself.Each of the particle ratios that were tried (20+2.5, 20+5, and 20+10)provided lower thermal conductivity than just 20 vol % BN. This meansthat in combination with boron nitride, these carbon blacks reduce thethermal conductivity of the composite compared to the composite withonly boron nitride and no carbon blacks.

FIG. 8 adds in the polymer composite that includes a mixture of BN andpartially crystallized carbon black. In this case, the addition ofcarbon black CB2 improves the thermally conductivity over BN alone. TheBN1-CB2 combination provides better thermal conductivity in the polymercomposite than the thermal conductivity that would be expected by addingtogether the thermally conductivity contributions that each componentparticle provides on its own. The BN1-CB2 combination contributes agreater amount to thermal conductivity than does an equivalent volumepercent of pure BN. For example, at total particulate volumes of greaterthan 25%, the trend lines show that the BN1-CB2 combination providesbetter thermal conductivity than an equivalent amount of BN1 only. Thus,by substituting a portion of the BN in a composite with a partiallycrystallized carbon black, cost can be reduced while actually increasingthermal conductivity. This is illustrated for ratios (by volume) of BNto CB of 2:1, 4:1 and 8:1 at total particulate loadings of 30 volume %,25 volume % and 22.5 volume %.

Example 4—

Composites were prepared according to the compositions listed in Table 6below, using Zytel ST7301NC polyamide 6 from Dupont as the polymer. BN2is Platelets 15/400 boron nitride available from 3M. The composites weremixed in a APV twin screw extruder supported by Baker Perkins having ascrew diameter of 27 mm and a length/diameter ratio of 40.5 and cooledwith a water bath. A #2 screw was used and the extruder was operated at300 rpm with an output rate of 8 kg/hr for two strands. Zones 2, 3, and9 were maintained at 250° C., zone 4 at 260° C. and zones 5-8 at 270° C.The melt die ranged between 260 and 272° C. Vent port 1 was open to theatmosphere, vent port 2 was closed, and vent port 3 was maintained undervacuum. The torque ranged between 33 and 40% except for the sample with30 vol % BN1, for which the torque was not stable. Thermal conductivityand volume resistivity were measured as described in Example 3 and arealso listed in Table 6 below. Mass flow index (MFI) was measuredaccording to ASTM D1238 (275° C./5 kg for all samples except neatpolymer, for which 275° C./2.16 kg).

TABLE 6 Avg. Avg. ST. Volume TC DEV Grade % [W/mK] [W/mK] MFI CB 1 + BN1CB1 5; 0.611 0.042 11.5 BN1 20 CB 1 + BN1 CB1 10; 0.649 0.049 0.8 BN1 20BN1 20 0.511 0.030 36.8 BN1 30 0.785 0.027 6.0 BN1 35 0.892 0.017 2.1CB2 + BN1 CB2 5; 0.636 0.030 13.3 BN1 20 CB2 + BN1 CB2 10; 0.761 0.0160.8 BN1 20 CB2 + BN2 CB2 10; 0.845 0.020 1.0 BN2 20 No CB 0.301 0.02926.9 CB2 25 0.705 0.032 — CB2 30 0.814 0.027 0 CB1 30 0.581 0.015 0

In addition, composites were produced using the HDPE of Example 3 butthe mixing methods of Example 4, using 20 vol % BN1 and 5 vol % CB2, toachieve a thermal conductivity of 1.116 +/−0.030 W/mK. This is less thanthe thermal conductivity of the same composite produced using the methodof Example 3. Without being bound by any particular theory, it isbelieved that the higher shear imparted by the twin screw extruder inExample 4 may have fractured some of the boron nitride platelets,reducing thermal conductivity in comparison to the composite producedusing the lower shear Brabender mixer in Example 3.

While several embodiments of the present invention have been describedand illustrated herein, those of ordinary skill in the art will readilyenvision a variety of other means and/or structures for performing thefunctions and/or obtaining the results and/or one or more of theadvantages described herein, and each of such variations and/ormodifications is deemed to be within the scope of the present invention.More generally, those skilled in the art will readily appreciate thatall parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the teachings of thepresent invention is/are used. Those skilled in the art will recognize,or be able to ascertain using no more than routine experimentation, manyequivalents to the specific embodiments of the invention describedherein. It is, therefore, to be understood that the foregoingembodiments are presented by way of example only and that, within thescope of the appended claims and equivalents thereto, the invention maybe practiced otherwise than as specifically described and claimed. Thepresent invention is directed to each individual feature, system,article, material, kit, and/or method described herein. In addition, anycombination of two or more such features, systems, articles, materials,kits, and/or methods, if such features, systems, articles, materials,kits, and/or methods are not mutually inconsistent, is included withinthe scope of the present invention.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Other elements may optionallybe present other than the elements specifically identified by the“and/or” clause, whether related or unrelated to those elementsspecifically identified, unless clearly indicated to the contrary.

All references, patents and patent applications and publications thatare cited or referred to in this application are incorporated in theirentirety herein by reference.

1. A thermoplastic composite polymer composition comprising: greaterthan 50% by weight of a polymer matrix; and a partially crystallizedfurnace carbon black dispersed in the polymer matrix at a concentrationof from 12 to 28 percent by weight, wherein the carbon black has an OANstructure of greater than 120 cm³/100 g and less than 200 cm³/100 g, asurface energy of less than 8 mJ/m², a percent crystallinity of lessthan 65% and a Raman microcrystalline planar size (La) of greater thanor equal to 28 Å.
 2. (canceled)
 3. The thermoplastic composite polymercomposition of claim 1 wherein the carbon black is formed by thermallytreating a furnace black at a temperature greater than 700° C. and lessthan 1800° C.
 4. The thermoplastic composite polymer composition ofclaim 1 wherein the polymer matrix comprises a copolymer or terpolymer.5. The thermoplastic composite polymer composition of claim 1 whereinthe polymer matrix comprises a polyolefin, a polystyrene, apolycarbonate, a polyamide, and/or a polyamine.
 6. (canceled) 7.(canceled)
 8. The thermoplastic composite polymer composition of claim 1further comprising a non-carbonaceous particle having a thermalconductivity of greater than 30 W/mK.
 9. The thermoplastic compositepolymer composition of claim 8 wherein the non-carbonaceous particle isselected from BN, MgO, ZnO, and Al₃O₂.
 10. The thermoplastic compositepolymer composition of claim 9 wherein the non-carbonaceous particlecomprises BN, and wherein the volume ratio of partially crystallizedcarbon black to BN is in the range of 1:1 to 1:10.
 11. (canceled) 12.The thermoplastic composite polymer composition of claim 1, wherein thethermal conductivity of the thermoplastic composite polymer compositionis at least 1.6× greater than the thermal conductivity of the polymermatrix.
 13. (canceled)
 14. (canceled)
 15. The thermoplastic compositepolymer composition of claim 1, wherein the partially crystallizedfurnace carbon black improves a thermal conductivity of thethermoplastic composite polymer composition at least 10% with respect toan untreated carbon black.
 16. A masterbatch comprising thethermoplastic composite polymer composition of claim
 1. 17. A polymerprecursor composition comprising: greater than 50% by weight of apolymer precursor comprising a polymerizable monomer or oligomer; and apartially crystallized furnace carbon black dispersed in the monomer oroligomer at a concentration of from 12 to 28 percent by weight, whereinthe carbon black has an OAN structure of greater than 120 cm³/100 g andless than 200 cm³/100 g, a surface energy of less than 8 mJ/m² and aRaman microcrystalline planar size (L_(a)) of greater than or equal to28 Å.
 18. The polymer precursor composition of claim 17 wherein thepolymer precursor comprises a precursor of a polymer selected fromthermoplastic polyolefins (TPO), polyethylene (PE), linear low density(LLDPE), low density (LDPE), medium density (MDPE), high density (HDPE),ultra-high molecular weight (UHMWPE), very low density polyethylene(VLDPE), metallocene medium density polyethylene (mLLDPE),polypropylene, copolymers of polypropylene, ethylene propylene rubber(EPR), ethylene propylene diene terpolymers (EPDM), acrylonitrilebutadiene styrene (ABS), acrylonitrile EPDM styrene (AES),styrene-butadiene-styrene (SBS), polyoxymethylene (POM), polyamides (PA)polyvinylchloride (PVC), tetraethylene hexapropylene vinylidenefluoridepolymers (THV), perfluoroalkoxy polymers (PFA), polyhexafluoropropylene(HFP), polyketones (PK), ethylene vinyl alcohol (EVOH), copolyesters,polyurethanes (PU), thermoplastic polyurethanes, polystyrene (PS),polycarbonate (PC), polybutylene terephthalate (PBT), polyethyleneterephthalate (PET), polypheneylene oxide (PPO), polyphenylene ether(PPE), an acrylic, an epoxy, silicone, a phenolic resin, a polyimide, aplastisol, and polyvinyl acetate.
 19. The polymer precursor compositionof claim 17, wherein the precursor comprises a precursor of apolyolefin, a polystyrene, a polycarbonate, a polyamide, and/or apolyamine.
 20. The polymer precursor composition of claim 17, furthercomprising a non-carbonaceous particle having a thermal conductivity ofgreater than 30 W/mK.
 21. The polymer precursor composition of claim 20,wherein the non-carbonaceous particle is selected from BN, MgO, ZnO, andAl₃O₂.
 22. The polymer precursor composition of claim 21, wherein thenon-carbonaceous particle comprises BN, and wherein the volume ratio ofpartially crystallized carbon black to BN is in the range of 1:1 to1:10.
 23. (canceled)
 24. The polymer precursor composition of claim 17,wherein following polymerization, a thermal conductivity of thepolymerized polymer precursor composition is at least 1.6× greater thanthe thermal conductivity of a polymerizate of the polymer precursor. 25.(canceled)
 26. (canceled)
 27. The polymer precursor composition of claim17, wherein the partially crystallized furnace carbon black improves athermal conductivity of a polymerizate of the polymer precursorcomposition by at least 10% with respect to an untreated carbon black.28. A product comprising the composite polymer composition of Claim 1,wherein the product is selected from wire and cable jacketing, 3Dprinted products, automotive parts, and LED casings and fixtures. 29.(canceled)
 30. (canceled)
 31. (canceled)
 32. (canceled)
 33. (canceled)34. (canceled)
 35. (canceled)
 36. (canceled)
 37. (canceled) 38.(canceled)